So this is how they expected the coolant system to work - cross flow !!

[UrS4boy]

The PNs are for an C4 AAN UrS4 but most (e.g. after-run pump, turbo coolant line, etc) will be the same for the 3B, ABY and ADU. Anyway, now I know why there is a water manifold.

[Jamo]

Is that diagram right? as AFAIK the aux water pump flows in the opposite direction of the main coolant on the S2

Let me find the pic

[UrS4boy]

Is that diagram right? as AFAIK the aux water pump flows in the opposite direction of the main coolant on the S2. Let me find the pic

The base diagram is from a VAG study guide I believe. I just added the thumbnail photos and PNs . I did not add or change the blue flow arrows.

[Jamo]

I know why thats the flow with the engine on, engine off flow is reversed http://www.s2forum.com/forum/showthread.php?t=12322

[UrS4boy]

I know why thats the flow with the engine on, engine off flow is reversed http://www.s2forum.com/forum/showthread.php?t=12322

Feel free to do a flow diagram with the engine off and the after-run pump on.

The point of the diagram, in my mind, was to show the purpose of the water manifold to help create even coolant flow *ACROSS* the head, not to be exact about the flow direction of the after-run pump under all situations.

But good to know anyway. Thanks Jamo. (I might modify my After-run pump post with this info) http://forums.quattroworld.com/s4s6/msgs/21503.phtml

[UrS4boy]

I know why thats the flow with the engine on, engine off flow is reversed http://www.s2forum.com/forum/showthread.php?t=12322

Further update - Fixed with a Notation (Thanks Jamo):